The present invention relates to filters for filtering contaminants from hydraulic fluid and more specifically relates to in-line filters.
When filters are subjected to relatively large pressure drops across their filtering elements, the latter may become damaged. One way of protecting these elements from damage has been to use pressure responsive valves for bypassing fluid around the filter elements in response to the pressure drop across the elements reaching an undesirable level. These protective devices are often remote from the filter elements and accordingly require additional lines for carrying the bypassed fluid. Also, these devices have the undersirable characteristic of bypassing unfiltered fluid to the function part of the hydraulic system.